Erosion resistant crossover for fracturing/gravel packing

ABSTRACT

An erosion resistant crossover which may be used in fracturing and/or gravel packing. In one aspect, a fluid delivery system for use in a subterranean well may comprise a fluid discharge apparatus including a flow passage, at least one discharge opening for discharging fluid from the flow passage to an exterior of the apparatus, and a flow diversion device operative to more evenly distribute flow through the opening by diverting fluid flow through the opening in a more upstream direction relative to fluid flow through the passage.

BACKGROUND

The present invention relates generally to operations performed and equipment utilized in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides an erosion resistant crossover which may be used for fracturing and/or gravel packing.

In fracturing and gravel packing operations, a fluid is pumped through a work string and is delivered to a wellbore. When fracturing, the fluid is forced under pressure into a formation intersected by the wellbore, and the fluid may also be circulated back to the surface. When gravel packing, the fluid is circulated back to the surface.

The fluid is combined with proppant to form a slurry in fracturing operations. The fluid is combined with a granular filtering material or “gravel” to form a slurry in gravel packing operations. The proppant and the granular material may each be sand, or either of them may be a synthetic material or other type of material.

Typically, such slurries are abrasive and gradually erode the equipment used to deliver the slurry into the wellbore. The equipment is expensive to replace or refurbish, and valuable time is consumed when the equipment becomes unusable due to erosion, for example, when multiple fracturing and/or gravel packing operations are performed using the same equipment. For example, crossovers (used to deliver fluid from an interior flow passage of the work string to the wellbore external to the work string) are relatively expensive to manufacture and typically experience significant erosion due in large part to a change in direction of the slurry therein.

Therefore, it may be seen that it would be beneficial to provide more erosion resistant equipment for fracturing and gravel packing operations, such as an erosion resistant crossover or other fluid discharge apparatus. Such erosion resistant equipment could find use in other applications, as well.

SUMMARY

In carrying out the principles of the present invention, in accordance with multiple embodiments described below, an erosion resistant fluid delivery system is provided which utilizes unique features to reduce or eliminate erosion of a fluid discharge apparatus thereof, or at least to confine a substantial amount of such erosion to a relatively inexpensive and conveniently replaced portion thereof. The system also reduces erosion of structures exterior to the fluid discharge apparatus.

In one aspect of the invention, a fluid delivery system for use in a subterranean well is provided by the invention. The system includes a fluid discharge apparatus having a flow passage, at least one discharge opening for discharging fluid from the flow passage to an exterior of the apparatus, and a flow diversion device operative to divert fluid flow through the opening in a more upstream direction relative to fluid flow through the passage. The flow diversion device may include at least one annular shaped obstruction in the passage. The obstruction may be circumferentially discontinuous. The flow diversion device may include multiple obstructions longitudinally spaced apart in the passage.

The flow diversion device can also include a shield positioned between the opening and the passage. The shield may have multiple ports for flow between the opening and the passage. The ports can intersect the passage at different flow areas of the passage.

The apparatus may include only a single opening. Alternatively, the apparatus may include at least two discharge openings, with one of the openings being upstream of another opening relative to flow through the passage. The flow diversion device may include one opening intersecting the passage at a flow area of the passage which is greater than a flow area of the passage at which another opening intersects the passage.

In another aspect of the invention, a fluid delivery system is provided which includes a fluid discharge apparatus. The fluid discharge apparatus has a longitudinal flow passage, at least one discharge opening for discharging fluid from the passage to an exterior of the apparatus, and at least one restriction to flow in the passage.

In yet another aspect of the invention, a fluid delivery system is provided which includes a fluid discharge apparatus in which a flow area of the passage decreases in a direction of flow through the passage.

In a further aspect of the invention, a fluid delivery system is provided which includes a fluid discharge apparatus with multiple openings for discharging fluid from the passage to an exterior of the apparatus. The openings are configured in a manner evenly longitudinally distributing fluid flow to the exterior of the apparatus.

In a still further aspect of the invention, a fluid delivery system is provided which includes a fluid discharge apparatus with a shield positioned between the passage and the opening. The shield has multiple ports permitting fluid flow therethrough from the passage to the opening. One port intersects the passage at a flow area of the passage which is greater than a flow area of the passage at which a second port intersects the passage.

These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partially cross-sectional view of an abrasive slurry delivery system embodying principles of the present invention;

FIG. 2 is an enlarged scale schematic cross-sectional view of a fluid discharge apparatus which may be used in the system of FIG. 1, the fluid discharge apparatus embodying principles of the invention;

FIG. 3 is a schematic cross-sectional view of a first alternate construction of the fluid discharge apparatus, taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged scale schematic quarter-sectional view of a second alternate construction of the fluid discharge apparatus;

FIG. 5 is a schematic quarter-sectional view of a third alternate construction of the fluid discharge apparatus;

FIG. 6 is a schematic quarter-sectional view of a fourth alternate construction of the fluid discharge apparatus;

FIG. 7 is a schematic cross-sectional view of a fifth alternate construction of the fluid discharge apparatus;

FIG. 8 is a schematic cross-sectional view of a second fluid discharge apparatus embodying principles of the invention;

FIG. 9 is a cross-sectional view of the second fluid discharge apparatus, taken along line 9-9 of FIG. 8;

FIG. 10 is a schematic cross-sectional view of a third fluid discharge apparatus embodying principles of the invention;

FIG. 11 is a schematic cross-sectional view of a fourth fluid discharge apparatus embodying principles of the invention;

FIG. 12 is a schematic cross-sectional view of a fifth fluid discharge apparatus embodying principles of the invention;

FIG. 13 is a side view of a protective shield of the fifth fluid discharge apparatus;

FIG. 14 is a schematic cross-sectional view of a sixth fluid discharge apparatus embodying principles of the invention;

FIG. 15 is a side view of the sixth fluid discharge apparatus;

FIG. 16 is a schematic cross-sectional view of a seventh fluid discharge apparatus embodying principles of the invention;

FIG. 17 is a side view of the seventh fluid discharge apparatus; and

FIG. 18 is a schematic cross-sectional view of an eighth fluid discharge apparatus embodying principles of the invention.

DETAILED DESCRIPTION

Representatively illustrated in FIG. 1 is a fluid delivery system 10 which embodies principles of the present invention. In the following description of the system 10 and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention. The embodiments are described merely as examples of useful applications of the principles of the invention, which is not limited to any specific details of these embodiments.

As depicted in FIG. 1, the system 10 is being used to flow fluid (indicated by arrows 12) into a wellbore 14. The fluid 12 is flowed through a work string 16, which would typically include additional equipment not shown in FIG. 1, such as one or more packers, well screens, service tools, etc. A fluid discharge apparatus 18 is used to discharge the fluid 12 from the work string 16 into the wellbore 14.

The fluid 12 may be combined with abrasive particles, such as proppant or gravel, to form a slurry. The flow of this fluid 12 into the wellbore 14 would typically cause erosion of the discharge apparatus 18 and other structures, such as casing 20 lining the wellbore 14. To protect the casing 20, a protective sleeve 22 may be included in the work string and positioned between the discharge apparatus 18 and the casing, so that the fluid 12 flowing outwardly through openings 24 in the discharge apparatus does not impinge directly on the casing.

In keeping with the principles of the invention, the system 10 includes features which function to reduce or substantially eliminate erosion of the discharge apparatus 18, the sleeve 22 (when used), other portions of the work string 16, and the casing 20 (for example, when the sleeve is not used). Where erosion does occur, it is preferably confined to relatively inexpensive and easily replaced elements.

In fracturing and gravel packing operations, a fluid discharge apparatus such as the apparatus 18 is generally referred to as a “crossover,” since fluid is typically both discharged laterally from an internal flow passage, and fluid is flowed longitudinally through additional passages in the apparatus (for example, for circulation back to the surface). Thus, these lateral and longitudinal fluid flows “cross” each other in a crossover. However, it should be clearly understood that the principles of the invention are not limited to use only in crossovers, or only in fracturing and gravel packing operations.

Experience has shown that the majority of erosion in crossovers occurs at downstream ends of the discharge openings. This is due at least in part to the severe change in direction from longitudinal flow in the internal passage to lateral flow through the openings. At the upstream ends of the discharge openings, the fluid can continue to flow longitudinally somewhat, but at the downstream ends of the openings, the fluid can no longer flow longitudinally and is forced to exit the openings in a substantially lateral direction.

It has been discovered by the present inventors that, if a greater proportion of the fluid can be diverted to flow laterally outward through more upstream portions of the discharge openings, thereby more evenly distributing the flow through the openings, then the severe change in direction of the fluid at the downstream ends of the openings will be significantly reduced, and the overall erosion of the discharge apparatus will also be significantly reduced. In addition, erosion of the structures external to the discharge openings will be less concentrated, due to more evenly longitudinally distributed flow of the fluid external to the discharge apparatus. These and other advancements in the art are described in more detail below.

Representatively illustrated in FIG. 2 is a lateral cross-section of a fluid discharge apparatus 26 which may be used for the discharge apparatus 18 in the system 10. The discharge apparatus 26 may also be used in other systems in keeping with the principles of the invention.

The discharge apparatus 26 has a generally tubular housing 28 with a flow passage 30 extending longitudinally therein. Openings 32 permit fluid to flow laterally from the passage 30 to an exterior of the housing 28. When used in the system 10, the fluid 12 would flow downwardly through the passage 30 and then be discharged through the openings 32 into the wellbore 14. The fluid 12 could then be circulated back to the surface via additional return circulation passages 34 formed longitudinally through a sidewall of the housing 28.

In order to divert fluid flowing through the passage 30 to exit the openings 32 more evenly, the discharge apparatus 26 includes a flow diversion device 36 positioned in the passage which diverts the flow more toward the upstream ends of the openings. The diversion device 36 is in the form of an annular or ring shaped obstruction 38 positioned longitudinally between the upstream and downstream ends of the openings 32. As depicted in FIG. 2, the obstruction 38 is cut out at each of the openings 32, so that the obstruction is circumferentially discontinuous.

In FIG. 3, another cross-sectional view of the discharge apparatus 26 is illustrated. This view depicts an alternate construction of the discharge apparatus 26, in which a diversion device 40 thereof has an annular shaped obstruction 42 which is circumferentially continuous. In this case, the obstruction 42 is formed on a generally tubular shield 44 positioned in the housing 28, so that the passage 30 extends through the shield.

In this manner, the shield 44 is positioned laterally between the passage 30 and the openings 32. The shield 44 inwardly overlies the peripheries of the openings 32, thereby eliminating or at least substantially reducing erosion of the housing 28 in these areas. The shield 44 also preferably protects the remainder of the interior of the housing 28 from erosion.

It will be appreciated that, if erosion in the discharge apparatus 26 does occur, it will be confined totally, or substantially exclusively, to the shield 44 rather than to the housing 28. Since the shield 44 is preferably much less expensive to manufacture than the housing 28, and the shield is relatively easy to replace, significant benefits are obtained by confining erosion to the shield in the discharge apparatus 26. The shield 44 is preferably made of a highly erosion resistant material, such as carbide, to reduce the frequency at which the shield is replaced.

As with the discharge apparatus 26 as depicted in FIG. 2, the obstruction 42 shown in FIG. 3 is positioned longitudinally between upstream ends 46 and downstream ends 48 of the openings 32. However, the obstruction 42 could be otherwise positioned, such as at or above the upstream ends 46, at or below the downstream ends, or where the openings 32 are longitudinally spaced apart in the discharge apparatus 26, the obstruction 42 may be positioned longitudinally between the openings.

The diversion device 40 operates to more evenly distribute the flow through the openings 32 by diverting a greater proportion of the fluid 12 to be discharged toward the upstream ends 46 of the openings, thereby reducing the proportion of the fluid discharged toward the downstream ends 48 of the openings. To accomplish this objective, the obstruction 42 forms a restriction 50 in the passage 30 by reducing a flow area of the passage. As depicted in FIG. 3, the restriction 50 is an inner diameter of the obstruction 42.

At this point it should be pointed out that many other types of restrictions can be used. The annular shaped obstructions 38, 42 described above are provided merely as examples of the wide variety of flow restrictions which could be used. Furthermore, it is not necessary for a diversion device to reduce a flow area of a passage, in keeping with the principles of the invention. Flow can be diverted in various ways, without reducing a passage's flow area.

Another alternate configuration of the discharge apparatus 26 is illustrated in FIG. 4. Again, an annular shaped obstruction 52 is used in a diversion device 54 of the discharge apparatus 26. However, in this example the obstruction 52 is a tapered ring, so that a somewhat gradual restriction 56 to flow through the passage 30 is presented.

The obstruction 52 could be formed directly on the housing 28 as depicted in FIG. 4, or it could be formed on a shield positioned in the housing, such as the shield 44 shown in FIG. 3. The obstruction 52 can have any shape. The obstruction 52 can be circumferentially continuous or discontinuous. The obstruction 52 can be positioned at, between, above or below the upstream and downstream ends of the openings 32, or between longitudinally spaced openings.

Another alternate configuration of the discharge apparatus 26 is illustrated in FIG. 5. In this configuration, a diversion device 58 includes multiple longitudinally spaced apart annular shaped obstructions 60, 62, 64. Only three such obstructions are depicted in FIG. 5, but any number can be used in keeping with the principles of the invention.

Each of the obstructions 60, 62, 64 presents a restriction 66 to flow through the passage 30 by decreasing a flow area of the passage. The use of multiple obstructions 60, 62, 64 also creates additional disruption, turbulence in, and resistance to the flow of the fluid 12 through the passage 30, which further restricts flow through the passage. This additional turbulence can be varied by varying the spacing between the obstructions 60, 62, 64.

As depicted in FIG. 5, the obstructions 60, 62 are spaced longitudinally farther apart than are the obstructions 62, 64. In this manner, the diversion device 58 operates to increase resistance to the flow of the fluid 12 through the passage 30 as the spacing between the obstructions 60, 62, 64 decreases. The resistance increases in the direction of the flow of the fluid 12 through the passage 30. Where the diversion device 58 is positioned between upstream and downstream ends 46, 48 of the openings 32, it will be appreciated that greater resistance to fluid flow though the passage 30 will exist toward the downstream ends of the openings than toward the upstream ends of the openings, thereby more evenly distributing the flow through the openings by diverting a greater proportion of the fluid 12 to flow outward toward the upstream ends of the openings.

The obstructions 60, 62, 64 could be formed directly on the housing 28 as depicted in FIG. 5, or they could be formed on a shield positioned in the housing, such as the shield 44 shown in FIG. 3. The obstructions 60, 62, 64 can be circumferentially continuous or discontinuous. The obstructions 60, 62, 64 can have any shape. The obstructions 60, 62, 64 can be positioned at, between, above or below the upstream and downstream ends of the openings 32, or between longitudinally spaced openings.

Referring additionally now to FIG. 6, another alternate construction of the discharge apparatus 26 is illustrated. As with the construction depicted in FIG. 5, the construction shown in FIG. 6 includes a diversion device 68 which includes three longitudinally spaced apart annular shaped obstructions 70, 72, 74. Again, any number of obstructions can be used in the diversion device 68.

However, unlike the obstructions 60, 62, 64 shown in FIG. 5, the obstructions 70, 72, 74 are equally spaced apart. Resistance to flow through the passage 30 is still increased in the direction of flow of the fluid 12 by successively reducing the flow area of the passage through the obstructions 70, 72, 74. That is, the farthest upstream obstruction 70 presents a restriction 76, the next downstream obstruction 72 presents a greater restriction 78 (further reduced flow area of the passage 30), and the farthest downstream obstruction 80 presents an even greater restriction 80 (most reduced flow area of the passage).

In this manner, the diversion device 68 operates to increase resistance to the flow of the fluid 12 through the passage 30 as the flow area of the passage decreases. The resistance increases in the direction of the flow of the fluid 12 through the passage 30. Where the diversion device 68 is positioned between upstream and downstream ends 46, 48 of the openings 32, it will be appreciated that greater resistance to fluid flow though the passage 30 will exist toward the downstream ends of the openings than toward the upstream ends of the openings, thereby more evenly distributing the flow through the openings by diverting a greater proportion of the fluid 12 to flow outward toward the upstream ends of the openings.

The obstructions 70, 72, 74 could be formed directly on the housing 28 as depicted in FIG. 6, or they could be formed on a shield positioned in the housing, such as the shield 44 shown in FIG. 3. The obstructions 70, 72, 74 can be circumferentially continuous or discontinuous. The obstructions 70, 72, 74 can have any shape. The obstructions 70, 72, 74 can be equally or unequally spaced apart. The obstructions 70, 72, 74 can be positioned at, between, above or below the upstream and downstream ends of the openings 32, or between longitudinally spaced openings.

Another alternate construction of the discharge apparatus 26 is illustrated in FIG. 7. One difference in the discharge apparatus 26 depicted in FIG. 7 is that, instead of the laterally aligned openings 32 as shown in FIG. 3, longitudinally spaced apart openings 82 are used to discharge the fluid 12 from the passage 30 to the exterior of the apparatus. Another difference is that a diversion device 84 of the discharge apparatus 26 includes obstructions 86, 88, 90, 92, 94 alternated longitudinally with the openings 82. Yet another difference is that the obstructions 86, 88, 90, 92, 94 have apertures 96, 98, 100, 102, 104 formed therethrough.

The apertures 96, 98, 100, 102, 104 present restrictions to flow of the fluid 12 through the passage 30. In this manner, a greater proportion of the fluid 12 is caused to flow through the more upstream openings 82. Note that a flow area of the passage 30 is reduced at each aperture 96, 98, 100, 102, 104, but that the flow area of the passage through each aperture is the same.

In addition, the resistance to flow through the obstructions 86, 88, 90, 92, 94 is increased in the direction of flow through the passage 30 by increasingly laterally offsetting the apertures 96, 98, 100, 102, 104 in the downstream direction. Note that an offset distance d between the farthest upstream apertures 96, 98 is smaller than an offset distance D between the farthest downstream apertures 102, 104.

The greater offset distance D produces a greater resistance to flow through the apertures 102, 104 as compared to the resistance to flow through the apertures 96, 98. Other techniques may be used instead of, or in combination with, the increased offset distance to increase resistance to flow in the downstream direction. For example, the obstructions 86, 88, 90, 92, 94 could be spaced closer together in the downstream direction, the flow area through each successive one of the apertures 96, 98, 100, 102, 104 could decrease in the downstream direction, etc.

The obstructions 86, 88, 90, 92, 94 could be formed directly on the housing 28 as depicted in FIG. 7, or they could be formed on a shield positioned in the housing, such as the shield 44 shown in FIG. 3. The obstructions 86, 88, 90, 92, 94 can be circumferentially continuous or discontinuous. The obstructions 86, 88, 90, 92, 94 can have any shape. The obstructions 86, 88, 90, 92, 94 can be equally or unequally spaced apart. The obstructions 86, 88, 90, 92, 94 can be positioned at, between, above or below the upstream and downstream ends of the openings 32, instead of between the longitudinally spaced openings 82.

Referring additionally now to FIG. 8, another fluid discharge apparatus 110 is illustrated. The discharge apparatus 110 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications.

The discharge apparatus 110 includes a generally tubular housing 112 having a longitudinal flow passage 114 therein and a single elongated opening 116 for discharging fluid from the passage to an exterior of the apparatus. Multiple return circulation passages 118 are formed longitudinally through a sidewall of the housing 112.

By providing only a single discharge opening 116 in the housing 112, an increased sidewall thickness of the housing can be provided between the opening and the return circulation passages 118. This increased sidewall thickness between the opening 116 and the passages 118 can be seen in the lateral cross-sectional view of the discharge apparatus 110 in FIG. 9.

In past designs, a crossover housing would become unusable when erosion of the housing sidewall permitted communication between a discharge opening and a return circulation passage. The increased sidewall thickness between the opening 116 and the passages 118 enables the housing 112 of the discharge apparatus 110 to withstand more erosion in this area before the housing becomes unusable.

In addition, it will be appreciated that even if the single opening 116 has the same flow area as might otherwise be provided by multiple openings in the housing 112, less restriction to flow is presented by the single opening than by multiple openings. Furthermore, the single opening 116 has a smaller periphery than the combined peripheries of multiple openings with the same flow area. Note that a single opening 116 may be used in any of the other discharge apparatuses 18, 26 described above, if desired.

Positioned in the housing 112 is a generally tubular shield 120. The passage 114 extends through the shield 120, and so in this manner the shield is positioned between the passage and the opening 116, inwardly overlying the periphery of the opening to protect it from erosion. The shield 120 may be made of an erosion resistant material, such as carbide.

When used in the system 10, the fluid 12 will flow longitudinally through the passage 114, and then laterally outward through a port 122 formed through a sidewall of the shield 120, and then laterally outward through the opening 116 to the exterior of the discharge apparatus 110. The opening 116 has an upstream end 124 and a downstream end 126 relative to the direction of flow of the fluid 12 through the passage 114. The shield 120 has a fluid diversion device 128 which functions to more evenly distribute flow through the opening 116 by diverting the flow of the fluid 12 more toward the upstream end 124 of the opening, thereby reducing erosion of the downstream end 126.

The diversion device 128 includes a tapered inner wall 130 of the shield 120. As depicted in FIG. 8, the wall 130 is generally conical (or frusto-conical) shaped, so that a flow area of the passage 114 decreases in the downstream direction of the flow through the passage. Thus, the flow area of the passage 114 at the downstream end 126 of the opening 116 is less than the flow area of the passage at the upstream end 124 of the opening. This induces the fluid 12 to flow more toward the upstream end 124 of the opening 116.

The tapered wall 130 presents a greater restriction to flow through the passage 114 at the downstream end 126 of the opening than at the upstream end of the opening 124. This restriction to flow gradually increases in the downstream direction of flow through the passage 114. The increased restriction to flow may begin at, above or below the upstream or downstream ends 124, 126 of the opening 116, between the upstream and downstream ends, or in any position relative to longitudinally spaced apart openings (such as openings 82 shown in FIG. 7) which may be provided in the discharge apparatus 110. The tapered wall 130 could be formed directly on the housing 112, instead of on the shield 120, if desired.

Another fluid discharge apparatus 132 is illustrated in FIG. 10. The discharge apparatus 132 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications. The discharge apparatus 132 is similar in many respects to the discharge apparatus 110 described above, and so the same reference numbers are used in FIG. 10 to indicate similar elements.

Instead of the shield 120 having the tapered wall 130, a diversion device 134 of the apparatus 132 includes an interior wall 136 having a stepped interior surface which progressively protrudes into the passage 114 in the direction of flow of the fluid 12. The stepped wall 136 is formed on a shield 138 which inwardly overlies a periphery of the opening 116. As the wall 136 progressively protrudes into the passage 114, the flow area of the passage decreases. The wall 136 thus presents an increased restriction to flow through the passage 114 and more evenly distributes flow through the opening 116 by diverting more of the fluid 12 to flow toward the upstream end 124 of the opening.

The increased restriction to flow may begin at, above or below the upstream or downstream ends 124, 126 of the opening 116, between the upstream and downstream ends, or in any position relative to longitudinally spaced apart openings (such as openings 82 shown in FIG. 7) which may be provided in the discharge apparatus 132. The stepped wall 136 could be formed directly on the housing 112, instead of on the shield 138, if desired.

Another fluid discharge apparatus 140 is illustrated in FIG. 11. The discharge apparatus 140 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications. The discharge apparatus 140 is similar in many respects to the discharge apparatuses 110, 132 described above, and so the same reference numbers are used in FIG. 11 to indicate similar elements.

Instead of the shields 120, 138 having the tapered and stepped walls 130, 136, a diversion device 142 of the apparatus 140 includes an inclined or tapered interior wall 144 having a flat planar flow deflection surface positioned opposite the opening 116. The sloped or tapered wall 144 is formed on a shield 146 which inwardly overlies a periphery of the opening 116. As the wall 144 progressively protrudes into the passage 114, the flow area of the passage decreases. The wall 144 thus presents an increased restriction to flow through the passage 114 and more evenly distributes flow through the opening 116 by diverting more of the fluid 12 to flow toward the upstream end 124 of the opening.

As depicted in FIG. 11, the wall 144 is flat. However, the wall 144 could have a convex flow deflection surface or a concave flow deflection surface, if desired. A concave flow deflection surface could be used to direct flow of the fluid 12 more toward the middle of the opening 116 and away from the periphery of the opening, to reduce erosion of the periphery of the opening.

The increased restriction to flow may begin at, above or below the upstream or downstream ends 124, 126 of the opening 116, between the upstream and downstream ends, or in any position relative to longitudinally spaced apart openings (such as openings 82 shown in FIG. 7) which may be provided in the discharge apparatus 140. The tapered wall 144 could be formed directly on the housing 112, instead of on the shield 146, if desired.

Another fluid discharge apparatus 148 is illustrated in FIG. 12. The discharge apparatus 148 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications. The discharge apparatus 148 is similar in many respects to the discharge apparatus 110 described above, and so the same reference numbers are used in FIG. 12 to indicate similar elements.

The discharge apparatus 148 includes a shield 150 having a tapered interior wall 152 much like the tapered wall 130 of the shield 120. However, a diversion device 154 of the discharge apparatus 148 also includes a port 156 which is designed to gradually elongate toward the downstream end 126 of the opening 116 as the fluid 12 flows through the port.

Initially, as depicted in FIG. 12, the fluid 12 flows outwardly through the port 156, through the upper portion of the opening 116, and eventually impinges on an area A of an outer tubular structure 158. The tubular structure 158 could be, for example, the casing 20 or sleeve 22 in the system 10. Flow of the fluid 12 through the port 156 gradually erodes the port, elongating it in the downstream direction.

Thus, the fluid 12 later impinges on an area B of the tubular structure 158, then area C, then area D, and finally area E. In this manner, the fluid 12 impinges on different areas of the tubular structure 158, which reduces the concentration of erosion on an interior surface 160 of the tubular structure.

In FIG. 13 a side elevational view of the shield 150 is illustrated. In this view the manner in which the port 156 elongates can be seen. Initially, the port 156 is configured as shown in solid lines in FIG. 13.

As the fluid 12 flows outward through the port 156, it elongates in a downstream direction (relative to the flow of the fluid through the passage 114). For example, after 50,000 pounds of proppant have been pumped with the fluid 12 through the port 156, it may have elongated so that its downstream end is at 162, directing a majority of the fluid to impinge on area B of the tubular structure 158. After 100,000 pounds of proppant have been pumped, the port 156 may have elongated so that its downstream end is at 164, directing a majority of the fluid to impinge on area C of the tubular structure 158. After 150,000 pounds of proppant have been pumped, the port 156 may have elongated so that its downstream end is at 166, directing a majority of the fluid to impinge on area D of the tubular structure 158. After 200,000 pounds of proppant have been pumped, the port 156 may have elongated so that its downstream end is at 168, directing a majority of the fluid to impinge on area E of the tubular structure 158.

Note that, as the port 156 elongates, its downstream end intersects the passage 114 at an increasingly reduced flow area. Thus, the tapered wall 152 and the configuration of the port 156 function in combination to divert the fluid 12 to flow more toward the upstream end 124 of the opening 116.

Referring additionally now to FIGS. 14 & 15, another fluid discharge apparatus 170 is illustrated. The discharge apparatus 170 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications. The discharge apparatus 170 is similar in some respects to the discharge apparatus 110 described above, and so the same reference numbers are used in FIGS. 14 & 15 to indicate similar elements.

Similar somewhat also to the discharge apparatus 148, the discharge apparatus 170 has features which function to reduce concentration of erosion on the interior surface of the casing 20, sleeve 22 or other structure 158 positioned external to the discharge apparatus. For this purpose, a housing 172 of the discharge apparatus 148 has multiple openings 174, 176, 178 formed through its sidewall providing communication between the passage 114 and the exterior of the discharge apparatus. The openings 174, 176, 178 are circumferentially and longitudinally spaced apart in the housing 172.

Preferably, the openings 174, 176, 178 are helically spaced apart. This configuration of the openings 174, 176, 178 is used to induce helical swirl in flow of the fluid 12 exterior of the openings. This helical swirl can be seen in FIG. 15. By inducing helical swirl in the fluid flow exterior of the discharge apparatus 170, the fluid flow is evenly longitudinally distributed exterior of the discharge apparatus. This reduces or eliminates any concentration of erosion on the interior of the casing 20, sleeve 22 or other structure 158 positioned external to the discharge apparatus 170.

The discharge apparatus 170 also includes features which function to more evenly distribute flow through the openings 174, 176, 178 by diverting more of the fluid 12 to flow through more upstream ones of the openings. For this purpose, in a flow diversion device 180 of the discharge apparatus 170, the farthest downstream opening 174 may have the smallest flow area. The next more upstream opening 176 may have a larger flow area than the opening 174. The farthest upstream opening 178 may have the largest flow area.

In addition, the flow diversion device 180 may include a tapered interior wall 182 formed on a shield 184 positioned in the housing 172. The shield 184 inwardly overlies the peripheries of the openings 174, 176, 178 and protects them from erosion. The shield 184 also includes multiple ports 186, 188, 190 corresponding to the openings 174, 176, 178.

The tapered wall 182 forms an increased restriction to flow through the passage 114 in the downstream direction, since a flow area of the passage decreases in the direction of flow through the passage. Note that the farthest downstream opening 174 intersects the passage 114 (via the port 186) at a relatively small flow area portion of the passage, the next upstream opening 176 intersects the passage (via the port 188) at a larger flow area portion of the passage, and the farthest upstream opening 178 intersects the passage (via the port 190) at the largest flow area portion of the passage.

In FIGS. 16 & 17, another fluid discharge apparatus 192 is illustrated. The discharge apparatus 192 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications. The discharge apparatus 192 is similar in many respects to the discharge apparatus 170 described above, and so the same reference numbers are used in FIGS. 16 & 17 to indicate similar elements.

The discharge apparatus 192 differs in at least one respect from the discharge apparatus 170 in that the openings 174, 176, 178 and corresponding ports 186, 188, 190 are not helically spaced apart. The openings 174, 176, 178 are still circumferentially and longitudinally spaced apart, and do function to evenly longitudinally distribute fluid flow to the exterior of the discharge apparatus 192. However, the configuration of the openings 174, 176, 178 in the discharge apparatus 192 may not function to induce helical swirl in the flow of the fluid 12 exterior of the openings.

Note that in each of the discharge apparatuses 170, 192, it is not necessary for the flow areas of the openings 174, 176, 178 to vary, or for the restriction to flow through the passage 114 to increase in the downstream direction. Any number of openings could be provided in the discharge apparatuses 170, 192. The increased restriction to flow may begin at, above or below any of the openings 174, 176, 178 which may be provided in the discharge apparatuses 170, 192. The tapered wall 182 could be formed directly on the housing 172, instead of on the shield 184, if desired.

Referring additionally now to FIG. 18, another fluid discharge apparatus 194 is illustrated. The discharge apparatus 194 may be used for the discharge apparatus 18 in the system 10, or it may be used in other applications. The discharge apparatus 194 is similar in many respects to the discharge apparatus 110 described above, and so the same reference numbers are used in FIG. 18 to indicate similar elements.

The discharge apparatus 194 differs in at least one respect from the discharge apparatus 110 in that a diversion device 196 of the discharge apparatus 194 includes multiple ports 198, 200 formed through a sidewall of a shield 202, as well as the tapered interior wall 130 formed on the shield. The ports 198, 200 are longitudinally spaced apart in the shield 202, and each port provides communication between the passage 114 and the single opening 116. Due to the tapered wall 130 in the shield 202, the farther downstream port 198 intersects the passage 114 at a smaller flow area of the passage than does the farther upstream port 200.

In addition, the farther downstream port 198 may have a smaller flow area than the farther upstream port 200. The combination of the decreasing flow area of the passage 114 due to the tapered wall 130 and the decreasing flow areas of the ports 198, 200 function to more evenly distribute flow through the opening 116 by diverting more of the fluid 12 to flow toward the upstream end 124 of the opening and away from the downstream end of the opening. This reduces erosion of the downstream end 126 of the opening 116 and more evenly longitudinally distributes flow of the fluid 12 external to the opening.

Note that it is not necessary for the flow areas of the ports 198, 200 to vary, or for the restriction to flow through the passage 114 to increase in the downstream direction. Any number of ports could be provided in the discharge apparatus 194. The increased restriction to flow may begin at, above or below any of the ports which may be provided in the discharge apparatus 194. The tapered wall 130 could be formed directly on the housing 112, instead of on the shield 202, if desired.

Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are within the scope of the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents. 

1. A fluid delivery system for use in a subterranean well, the system comprising: a fluid discharge apparatus including a flow passage, at least one discharge opening for discharging fluid from the flow passage to an exterior of the apparatus, and a flow diversion device operative to more evenly distribute flow through the opening by diverting fluid flow through the opening in a more upstream direction relative to fluid flow through the passage.
 2. The system of claim 1, wherein the flow diversion device comprises at least one annular shaped obstruction in the passage.
 3. The system of claim 1, wherein the flow diversion device comprises a restriction to flow through the passage increasing in a downstream direction relative to fluid flow through the passage.
 4. The system of claim 1, wherein the flow diversion device comprises multiple obstructions longitudinally spaced apart in the passage.
 5. The system of claim 1, wherein the flow diversion device comprises a shield positioned between the opening and the passage, the shield having multiple ports for flow between the opening and the passage, the ports intersecting the passage at different flow areas of the passage.
 6. The system of claim 1, wherein the apparatus includes at least first and second discharge openings, the first opening being upstream of the second opening relative to flow through the passage, and wherein the flow diversion device comprises the first opening intersecting the passage at a first flow area of the passage, the second opening intersecting the passage at a second flow area of the passage, and the first flow area being greater than the second flow area.
 7. The system of claim 1, wherein the apparatus includes only a single opening.
 8. The system of claim 1, wherein the apparatus includes multiple openings configured to induce helical flow of fluid on the exterior of the apparatus.
 9. The system of claim 1, wherein the apparatus includes multiple openings configured in a manner evenly longitudinally distributing flow to the exterior of the apparatus.
 10. The system of claim 1, wherein the apparatus includes multiple openings, and wherein the flow diversion device comprises a flow area of the openings decreasing in a downstream direction relative to fluid flow through the passage.
 11. A fluid delivery system for use in a subterranean well, the system comprising: a fluid discharge apparatus including a longitudinal flow passage, at least one discharge opening for discharging fluid from the passage to an exterior of the apparatus, and at least one restriction to flow in the passage.
 12. The system of claim 11, wherein the restriction is due to a generally annular shaped obstruction in the passage.
 13. The system of claim 11, wherein the apparatus includes at least two openings, and wherein the restriction is positioned between the openings.
 14. The system of claim 11, wherein the opening has upstream and downstream ends relative to a direction of flow through the passage, and wherein the restriction diverts fluid flow in a direction from the downstream end toward the upstream end of the opening while permitting fluid flow through the downstream end of the opening.
 15. A fluid delivery system for use in a subterranean well, the system comprising: a fluid discharge apparatus including a longitudinal flow passage, at least one discharge opening for discharging fluid from the passage to an exterior of the apparatus, and a flow area of the passage decreasing in a direction of flow through the passage.
 16. The system of claim 15, wherein an interior wall progressively protrudes into the passage and decreases the flow area of the passage in the direction of flow through the passage, and wherein the wall is positioned opposite the opening.
 17. The system of claim 15, wherein the opening has upstream and downstream ends relative to the direction of flow through the passage, and wherein the decreasing flow area of the passage diverts fluid flow toward the upstream end of the opening while permitting fluid flow through the downstream end of the opening.
 18. The system of claim 15, wherein the opening has upstream and downstream ends relative to the direction of flow through the passage, and wherein the decreasing flow area of the passage diverts fluid flow in a direction from the downstream end toward the upstream end of the opening while permitting fluid flow through the downstream end of the opening.
 19. The system of claim 15, wherein the opening has an upstream end relative to the direction of flow through the passage, and wherein the decreasing flow area of the passage diverts fluid flow toward the upstream end of the opening while permitting fluid flow through the downstream end of the opening.
 20. The system of claim 15, wherein the apparatus includes multiple openings, a first opening being positioned upstream of a second opening relative to the direction of flow through the passage, and wherein the decreasing flow area of the passage diverts fluid flow from the second opening to the first opening while permitting fluid flow through the second opening. 